C++实现在一个字符串中寻找最大子串

//#include "stdafx.h"
#include<iostream>
#include<vector>
#include<string>
#include<utility>
using namespace std;
pair<int ,string> fun(const string &s)
{
vector<string> substrs;
string substr;
int length=s.length();
for(int i=0;i<length;++i)
{
substrs.push_back(s.substr(i,length-i));

}
cout<<"后缀子串分别为"<<endl;
for(vector<string>::size_type index=0;index!=substrs.size();++index)
cout<<substrs[index]<<endl;
int count=0,maxcount=0;
for(int i=0;i<length;++i)
{
for(int j=i+1;j<length;++j)
{   count=1;
if(substrs[i].substr(0,j)==substrs[j].substr(0,j))
{
++count;
for(int k=j+(j-i);k<length;k+=j-i)
{
if(substrs[i].substr(0,j-i)==substrs[k].substr(0,j-i))
{
++count;
}
else
break;

}
if(count>maxcount)
{
maxcount=count;
substr=substrs[i].substr(0,j-i);

}
}

}
}
return  make_pair(maxcount,substr);
}
int main()
{   string s("abcbcbcabc");
pair<int,string> pair;
pair=fun(s);
cout<<pair.second<<" "<<pair.first<<endl;

system("pause");
return 0;
}